As is generally well known, truck mounted brake rigging for a railcar is supported by rigid rectangular guide members that engage channels or side pockets in the railcar truck side frame for sliding reciprocal movement therewithin. The end guide members, also commonly called end feet, end lugs or guide lugs, are either secured to ends of the brake beams or the brake head assembly mounted on the end of the brake beam. As the brake system is applied and released, the end members slide up and down the side frame pockets to guide brake shoes into proper engagement with the wheel threads. It is further generally known that friction during such sliding movement between steel end members and steel side frame channels or pockets prevents uniform application of all brake shoes of the brake rigging and results in uneven wear of the brake shoes.
Prior to conception and development of the instant invention, efforts have been made to reduce friction and improve train handling during brake application.
U.S. Pat. No. 5,682,964 issued to Murphy teaches a brake beam wear liner being a generally U-shape and configured for insertion into the side frame channel or pocket. The wear liner is molded from a polymer based material. However, it has been found that such wear liners become damaged over time resulting in higher than desirable replacement and maintenance costs.
U.S. Pat. No. 4,480,721 also issued to Murphy teaches a snap-on slide bearing that essentially surrounds at least top and bottom surfaces of the end member and having a projection on a bottom surface of one wall thereof that is sized for snap fit into a recess in the upper surface of the end member. The slide bearing is manufactured from ultra high molecular weight polyethylene material. Such sliding bearing may be used in combination with the wear liner of U.S. Pat. No. 5,682,964.
Teachings of U.S. Pat. Nos. 5,682,964 and 4,480,721 are incorporated hereby by reference thereto.
However, there is a further need for an arrangement to reduce friction between the end member and the side frame channel or pocket, so as to improve operating life of the wear liner, promulgate even brake shoe wear and improve train handling during brake application.